Inorganic coordination compounds of biological interest are being examined to determine the role of the metal ions in the relevant biological processes. Metalloporphyrins are being prepared as model systems involving electron transfer (the cytochromes), alkyl transfer (Vitamin B12) and ligation of small molecules such as N2, CO and O2 (hemoglobin). The techniques are those of physical inorganic chemistry such as magnetochemistry and magnetic resonance, spectroscopy and examination of the dynamics of the reactions by kinetic methods.